Anterior Skull

Anterior Skull

Sections

Key Functions
Cranial Bones
Facial Bones
Additional Skull Features

Key Functions

Key functions of the skull:

• Protects the brain and associated sensory organs.
• Provides attachment sites for the facial and neck muscles.

The skull itself comprises:

• 8 Cranial bones that enclose the brain
• 14 Facial bones that protect entryway to nasal and oral cavities, and provide muscle attachment sites.

Bones of the ear:

Cranial Bones

The cranial bones include unpaired and paired bones.

The unpaired cranial bones:

Frontal

• Forms the forehead and superior rim of eye orbits.
• Supraorbital margin is the bony ridge framing the orbit superiorly
• Supraorbital notch/foramen provides passageway for neurovascular structures.

Occipital

• Contributes to the posterior and inferior surface and base of the skull.

Sphenoid

• A bat-shaped bone that spans the width of the skull.

Ethmoid

• An irregularly shaped bone that lies deep within the skull.
• Contributes superior and middle nasal conchae.

The paired cranial bones:

Parietal

• Comprise the superior and lateral aspects of the skull.

Temporal

• Comprise the inferior portion of the lateral skull.

Facial Bones

The facial bones include unpaired and paired bones.

The unpaired facial bones:

Vomer

• Contributes to the nasal septum.

Mandible

• The bone of the lower jaw.
• Alveolar margin houses lower teeth.
• Mental foramen for neurovascular structures.

The paired facial bones:

Zygomatic

• Form the inferior margins of the orbits and the lateral cheekbones.

Lacrimal

• Contribute to the medial walls of the orbits.

Nasal

• Comprise the bridge of the nose.

Inferior nasal conchae

• Lie within the nasal cavity.

Palatine

• Contribute a small portion to the medial orbit wall (but chiefly contribute to the hard palate of the oral cavity).

Maxilla

• Fuse at the midline of the face to form the medial and inferior orbit walls, cheeks, and upper jaw.
• Infraorbital foramen for neurovascular structures.
• Alveolar margin is the border of the maxilla where the upper teeth are housed.

Additional Skull Features

Spaces within the eye orbit:

• The superior orbital fissure is a wide space within the sphenoid (specifically, between the greater and lesser wings).
• The inferior orbital fissure is the space between the sphenoid, zygomatic, and maxillary bones.
• The optic foramen is the opening to the optic canal, through which the optic nerve (cranial nerve II) passes.

Features of the nasal cavity:

• Nasal septum separates the nasal cavity into right and left sides.
  • Comprises two different bones:
    Superiorly: Perpendicular plate of the ethmoid bone.
    Inferiorly: The vomer bone comprises the inferior portion.